P1480: SPLENIC SEQUESTRATION IS MORE COMMON IN SCD-S/Β0-THAL THAN IN SCD-S/S PATIENTS: RESULTS FROM THE GERMAN SCD REGISTRY
Authors: P. Allard, L. Tagliaferri, S. Lobitz, H. Cario, A. Jarisch, R. Grosse, S. Ebert, M. Bleeke, L. Oevermann, D. Hakimeh, A. Kulozik, J. Kunz
Journal: HemaSphere (2022)

Background: The national German SCD registry collects data on the genotype, the presentation, complications and treatment of patients with SCD both retrospectively and prospectively. Currently, 820 patients are enrolled. Compared to other cohorts of patients with SCD, these patients are ethnically more heterogeneous and more frequently treated with hydroxyurea (HU) [1, 2]. Aims: We aim at characterising the genotypes, complications, treatment and laboratory parameters in patients with heterozygous SCD (SCD-S/C, SCD-S/β0-thal, SCD-S/β+-thal) enrolled in the German SCD Registry. Methods: The German SCD registry documents β-globin genotype, α-thalassemia genotype and four genetic modifiers of HbF synthesis (BCL11A rs1427407, rs7606173; HMIP rs66650371; HBG2 rs7482144). The genotypes were correlated with laboratory parameters (total hemoglobin, MCV, reticulocytes, fetal hemoglobin, bilirubin, LDH), complications (prospectively collected: vasoocclusive crises (VOC), acute chest syndrome (ACS), red blood cell (RBC) transfusions; retrospectively collected: VOC, splenic sequestration, splenectomy) and treatment (HU, red blood cell transfusions). For the analysis of laboratory parameters and complications, patients of two years of age or older were included. Results: We identified 88 patients with SCD-S/C (10,7% of all patients enrolled), 37 with SCD-S/β0-thal (4,5%), 50 with SCD-S/β+-thal (6,1%), and six patients (0,7%) with other genotypes (3 SCD-S/HPFH, 2 SCD-S/D Punjab, 1 SCD-S/OArab). The most recurrent β+-thalassemia mutation was IVS-I-110 G>A (n=18 patients). In contrast to patients with SCD-S/C, who originated almost exclusively from sub-Saharan Africa, patients with SCD-S/β0-thal and SCD-S/β+-thal originated mostly from the mediterranean region and carried HbF-boosting alleles more frequently. The majority of patients were prescribed HU (SCD-S/β0-thal 97%, SCD-S/β+-thal 79%, SCD-S/C 60%). The prospectively documented frequency of VOC, ACS and red blood cell transfusions per patient year was lowest in SCD-S/C (Table 1). For all patients aged between five and 18 years at registration, we analysed retrospectively collected data for the proportion of patients who had ever experienced typical complications of SCD, stratified according to the genotype. Splenic sequestration, splenectomy and pain crises were rare in SCD-S/C compared to SCD-S/S. In contrast, patients with SCD-S/β0-thal had suffered from splenic sequestration more frequently and had undergone splenectomy more often compared to SCD-S/S (Table 1). Image:Summary/Conclusion: The overall frequency of complications of SCD is highest in homozygous SCD and lowest in SCD-S/C. With the most frequent β+-mutation being IVS-I-110 G>A among our patients, further data on the rare complications such as sepsis and stroke are required in order to guide the decision which patients will likely benefit from penicillin prophylaxis and screening by transcranial Doppler ultrasound.